My baby girl heartbeat is 156 bpm ... I am 16+2 and they said it is still early but it looks like a baby girl!
My little mans heart beat was exactly the same as my little miss' the whole way through we were thinking another girl so we did a 4d scan at 16 weeks and he flashed his bits to us :)
My lil guy is always at 150, but I agree with the top post!
Heartbeat really got nothing to do with the gender. It's just a old wifes tale, lol.